Chronic calcineurin inhibitor nephrotoxicity-lest we forget

Calcineurin inhibitor (CNI) nephrotoxicity was recognized in Cambridge in the late 1970s. The vasoconstrictor impact of cyclosporine (CsA) and to a lesser extent tacrolimus, in both acute and chronic settings, results from a decrease in vasodilators and increase in vasconconstrictors while direct tubular toxicity results from blockade of mitochondrial permeability transition pores and inhibition of prolyl isomerase. A biopsy of native kidneys of recipients of CNIs reveals nephrotoxicity as the most common pathological diagnosis with chronic CNI toxicity and hypertension the primary problems. A long-term study of randomized clinical trials with up to 20 years of follow-up shows inferiority of both renal function and graft survival for continuous CsA compared to either CsA withdrawal or continuous azathioprine and prednisolone. Pathological hallmarks of chronic CNI nephrotoxicity include stripped interstitial fibrosis, arteriolar hyalinosis and glomerular sclerosis, but with the exception of nodular arteriolar hyalinosis the findings are non specific. The model for chronic renal allograft loss must be multifactorial with both immune and nonimmune factors operating dependent upon an individual's risk factors for cell and/or antibody-mediated rejection, CNI nephrotoxicity and recurrent disease. Better outcomes will require early diagnosis and individualization of therapy dependent upon the dominant mechanisms impacting each patient. The revisionist view put forward by some senior, experienced and thoughtful individuals, challenges the concept of chronic CNI nephrotoxicity as an important clinical entity. By implication, the view that appears to be promoted is as follows: we need not fear-prolonged exposure to CNIs, and in seeking better long-term solutions for transplant recipients, we have forgotten alloimmunity. It is thus apparent that we must revisit the data and again question the basis for chronic CNI nephrotoxicity in current clinical practice. This contribution to the debate will focus on the evidence that CNIs are nephrotoxic and that their impact needs to be limited if we are to improve long-term outcomes after transplantation, leaving others to promote the contrary perspective and perhaps also to reflect on the largely unproven impact of the steroid avoidance and other minimization strategies so prevalent today.

Screening for renal cancer in recipients of kidney transplants

BACKGROUND

Renal cancer is the most common solid organ cancer in the kidney transplant population with an excess risk ~ 5-fold greater than the general population. It is uncertain whether routine screening for renal cancer is cost-effective. The aim of our study is to estimate the costs and health benefits of ultrasonographic (US) screening for renal cancer in the kidney transplant population.

METHODS

A Markov model was developed to compare the costs and benefits in a cohort of kidney transplant recipients (n = 1000, aged 18-69 years), who underwent annual and biennial US screening for renal cancer, compared with a cohort that did not.

RESULTS

For recipients of kidney transplants aged 18-69 years, the incremental cost-effectiveness ratio (ICER) for routine US screening ranged from $252,100/LYS for biennial screening to $320,988/LYS for annual screening. A total of two and one cancer deaths were averted in the annually and biennially screened population, with a relative cancer-specific mortality reduction by 25% and 12.5%, respectively. Using a series of sensitivity analyses, the ICER was most sensitive to the costs and test specificity of ultrasonography, prevalence of disease, and the risk of graft failure in the screened population.

CONCLUSIONS

Routine screening for renal cancer may reduce the risk of cancer-related deaths in recipients of kidney transplants. Uncertainties, however, exist in the model's influential variables including the risk of graft failure among those who received contrast-enhanced diagnostic computer tomography. Given the available evidence, routine screening for renal cancers may not be cost-effective for recipients of kidney transplants.

The KDIGO review of the care of renal transplant recipient

This review highlights the key messages from the KDIGO (Kidney Disease: Improving Global Outcomes) clinical practice guidelines for care of kidney transplant recipients, which were written to be global guidelines irrespective of the regulatory, fiscal, cultural, socioeconomic, or geographical environment. The distillation of 3168 randomized control trials, 7543 cohort studies, and 1609 reviews led to recommendations rated by the strength of supporting evidence and the quality of the data from A to D. Despite this, the quality of the evidence is surprisingly low for the majority of decisions that are routinely taken in all transplant units throughout the world, highlighting the needs for properly designed randomized controlled trials. The principle areas covered in the guidelines include immunosuppression, management of acute rejection, monitoring of the patient and graft, chronic allograft injury, kidney biopsy, nonadherence, vaccination, infectious diseases, cardiovascular risk management, malignancy, bone disease, pediatric growth, lifestyle, fertility, and mental health. This review highlights a number of these areas for consideration focusing on the different types of evidence that we use in daily clinical practice.

Effect of reduced immunosuppression after kidney transplant failure on risk of cancer: population based retrospective cohort study

OBJECTIVE

To compare cancer incidence in kidney transplant recipients during periods of transplant function (and immunosuppression) and after transplant failure (when immunosuppression is ceased or reduced). Design, setting, and participants Nationwide, population based retrospective cohort study of 8173 Australian kidney transplant recipients registered on the Australia and New Zealand Dialysis and Transplant Registry who first received a transplant during 1982-2003. Incident cancers were ascertained using linkage with national cancer registry records.

MAIN OUTCOME MEASURES

Cancer-specific standardised incidence ratios for periods of transplant function and for dialysis after transplant failure. Incidence was compared between periods using multivariate incidence rate ratios adjusted for current age, sex, and duration of transplantation.

RESULTS

All cases of Kaposi's sarcoma occurred during transplant function. Standardised incidence ratios were significantly elevated during transplant function, but not during dialysis after transplant failure, for non-Hodgkin's lymphoma, lip cancer, and melanoma. For each of these cancers, incidence was significantly lower during dialysis after transplant failure in multivariate analysis (incidence rate ratios 0.20 (95% CI 0.06 to 0.65) for non-Hodgkin's lymphoma, 0.04 (0.01 to 0.31) for lip cancer, and 0.16 (0.04 to 0.64) for melanoma). In contrast, standardised incidence ratios during dialysis after transplant failure remained significantly elevated for leukaemia and lung cancer, and cancers related to end stage kidney disease (kidney, urinary tract, and thyroid cancers), with thyroid cancer incidence significantly higher during dialysis after transplant failure (incidence rate ratio 6.77 (2.64 to 17.39)). There was no significant difference in incidence by transplant function for other cancers.

CONCLUSIONS

The effect of immunosuppression on cancer risk is rapidly reversible for some, but not all, cancer types. Risk reversal was mainly observed for cancers with a confirmed infectious cause. Risk of other cancers, especially those related to end stage kidney disease, remained significantly increased after reduction of immunosuppression.

Interleukin 2 receptor antagonists for kidney transplant recipients

BACKGROUND

Interleukin 2 receptor antagonists (IL2Ra) are used as induction therapy for prophylaxis against acute rejection in kidney transplant recipients. Use of IL2Ra has increased steadily since their introduction, but the proportion of new transplant recipients receiving IL2Ra differs around the globe, with 27% of new kidney transplant recipients in the United States, and 70% in Australasia receiving IL2Ra in 2007.

OBJECTIVES

To systematically identify and summarise the effects of using an IL2Ra, as an addition to standard therapy, or as an alternative to another immunosuppressive induction strategy.

SEARCH STRATEGY

We searched the Cochrane Renal Group's specialised register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE to identify new records, and authors of included reports were contacted for clarification where necessary.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in all languages comparing IL2Ra to placebo, no treatment, other IL2Ra or other antibody therapy.

DATA COLLECTION AND ANALYSIS

Data was extracted and assessed independently by two authors, with differences resolved by discussion. Dichotomous outcomes are reported as relative risk (RR) and continuous outcomes as mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

We included 71 studies (306 reports, 10,537 participants). Where IL2Ra were compared with placebo (32 studies; 5,784 patients) graft loss including death with a functioning graft was reduced by 25% at six months (16 studies: RR 0.75, 95% CI 0.58 to 0.98) and one year (24 studies: RR 0.75, 95% CI 0.62 to 0.90), but not beyond this. At one year biopsy-proven acute rejection was reduced by 28% (14 studies: RR 0.72, 95% CI 0.64 to 0.81), and there was a 19% reduction in CMV disease (13 studies: RR 0.81, 95% CI 0.68 to 0.97). There was a 64% reduction in early malignancy within six months (8 studies: RR 0.36, 95% CI 0.15 to 0.86), and creatinine was lower (7 studies: MD -8.18 micromol/L 95% CI -14.28 to -2.09) but these differences were not sustained.When IL2Ra were compared to ATG (16 studies, 2211 participants), there was no difference in graft loss at any time point, or for acute rejection diagnosed clinically, but the was benefit of ATG therapy over IL2Ra for biopsy-proven acute rejection at one year (8 studies:, RR 1.30 95% CI 1.01 to 1.67), but at the cost of a 75% increase in malignancy (7 studies: RR 0.25 95% CI 0.07 to 0.87) and a 32% increase in CMV disease (13 studies: RR 0.68 95% CI 0.50 to 0.93). Serum creatinine was significantly lower for IL2Ra treated patients at six months (4 studies: MD -11.20 micromol/L 95% CI -19.94 to -2.09). ATG patients experienced significantly more fever, cytokine release syndrome and other adverse reactions to drug administration and more leucopenia but not thrombocytopenia. There were no significant differences in outcomes according to cyclosporine or tacrolimus use, azathioprine or mycophenolate, or to the study populations baseline risk for acute rejection. There was no evidence that effects were different according to whether equine or rabbit ATG was used.

AUTHORS' CONCLUSIONS

Given a 38% risk of rejection, per 100 recipients compared with no treatment, nine recipients would need treatment with IL2Ra to prevent one recipient having rejection, 42 to prevent one graft loss, and 38 to prevent one having CMV disease over the first year post-transplantation. Compared with ATG treatment, ATG may prevent some experiencing acute rejection, but 16 recipients would need IL2Ra to prevent one having CMV, but 58 would need IL2Ra to prevent one having malignancy. There are no apparent differences between basiliximab and daclizumab. IL2Ra are as effective as other antibody therapies and with significantly fewer side effects.

The pattern of excess cancer in dialysis and transplantation

BACKGROUND

After transplantation, cancer risk varies from no increase for several common cancers to a many-fold increase for a number of, chiefly virus-associated, cancers. The smaller excess of cancer in dialysis has been less well described, but two studies suggested that impaired immunity might be responsible.

METHODS

In a population-based cohort study of 28 855 patients who received renal replacement therapy (RRT), we categorized incident cancers as end-stage kidney disease (ESKD) related, immune deficiency related, not related to immune deficiency, or of uncertain status, according to whether they were, or were not, increased in published reports of cancer in ESKD prior to starting RRT, organ transplantation or human immunodeficiency virus infection. Standardized incidence ratios for, and excess burdens of, cancer were calculated for all persons normally resident in Australia starting treatment by dialysis or renal transplantation from 1982 to 2003.

RESULTS

The risk for ESKD-related cancers was increased 4-fold in dialysis and during transplant function. For immune deficiency-related cancers, the increase was 1.5 (95% CI 1.3-1.6) times in dialysis, and 5-fold after transplantation. ESKD- or immune deficiency-related cancers contributed to approximately 90% of the excess burden of cancer, 48% and 36%, respectively, in dialysis, and 10% and 78% after transplantation. The remaining excess malignancy was contributed by cancers whose relationship with ESKD and immune deficiency is not yet certain.

CONCLUSIONS

In RRT, the increase in cancer is restricted, largely if not wholly, to cancers with origins in ESKD or related to immune deficiency. For the former, the cancer risk is similar in dialysis and transplantation, but for immune deficiency-related cancers, the relative risk is much greater after transplantation.

Tirofiban and activated protein C synergistically inhibit the Instant Blood Mediated Inflammatory Reaction (IBMIR) from allogeneic islet cells exposure to human blood

Instant blood mediated inflammatory reaction (IBMIR) occurs when islets are exposed to blood and manifests clinically as portal vein thrombosis and graft failure. The aim of this study was to determine the impact of recombinant human activated protein C (rhAPC) and platelet inhibition on IBMIR in order to develop a better targeted treatment for this condition. Five thousand human islet cell equivalents (IEQ) were mixed in a PVC loop system with 7 mL of ABO compatible human blood and incubated with rhAPC, either alone or in combination with tirofiban. Admixing human islets and blood caused rapid clot formation, consumption of platelets, leukocytes, fibrinogen, coagulation factors and raised d-dimers. Islets were encased in a fibrin and platelet clot heavily infiltrated with neutrophils. Tirofiban monotherapy was ineffective, whereas rhAPC monotherapy prevented IBMIR in a dose-dependent manner, preserving islet integrity while maintaining platelet and leukocyte counts, fibrinogen and coagulation factor levels, and reducing d-dimer formation. The combination of tirofiban and low-dose rhAPC inhibited IBMIR synergistically with an efficacy equal to high dose rhAPC. Tirofiban and rhAPC worked synergistically to preserve islets, suggesting that co-inhibition of the platelet and coagulation pathways' contribution to thrombin generation is required for the optimal anti-IBMIR effect.

Association of CKD and cancer risk in older people

People with ESRD are at increased risk for cancer, but it is uncertain when this increased risk begins in the spectrum of chronic kidney disease (CKD). The aim of our study was to determine whether moderate CKD increases the risk for cancer among older people. We linked the Blue Mountains Eye Study, a prospective population-based cohort study of 3654 residents aged 49 to 97 yr, and the New South Wales Cancer Registry. During a mean follow-up of 10.1 yr, 711 (19.5%) cancers occurred in 3654 participants. Men but not women with at least stage 3 CKD had a significantly increased risk for cancer (test of interaction for gender P = 0.004). For men, the excess risk began at an estimated GFR (eGFR) of 55 ml/min per 1.73 m2 (adjusted hazard ratio [HR] 1.39; 95% confidence interval [CI] 1.00 to 1.92) and increased linearly as GFR declined. For every 10-ml/min decrement in eGFR, the risk for cancer increased by 29% (adjusted HR 1.29; 95% CI 1.10 to 1.53), with the greatest risk at an eGFR <40 ml/min per 1.73 m2 (adjusted HR 3.01; 95% CI 1.72 to 5.27). The risk for lung and urinary tract cancers but not prostate was higher among men with CKD. In conclusion, moderate CKD (stage 3) may be an independent risk factor for the development of cancer among older men but not women, and the effect of CKD on risk may vary for different types of cancer.

Immunosuppression and other risk factors for lip cancer after kidney transplantation

Incidence of lip cancer is markedly increased after kidney transplantation. Immunosuppression and other risk factors for lip cancer were investigated in a population-based, nationwide cohort of 8,162 kidney transplant recipients registered on the Australia and New Zealand Dialysis and Transplant Registry (1982-2003). Lip cancer diagnoses were ascertained using probabilistic data linkage with the Australian National Cancer Statistics Clearing House. Standardized incidence ratios were used to compare lip cancer risk by subsite of lip and during periods of transplant function and failure. Risk factors during the first functioning transplant were examined using multivariate Poisson regression. Lip cancer was diagnosed in 203 patients. All cases were of squamous cell origin and mostly (77%) affected the lower vermillion. Cases occurred predominantly during periods of transplant function, with incidence decreasing to pretransplantation level on transplant failure and cessation of immunosuppression. During transplant function, cancer of the lower vermillion was associated with increasing year of age [incidence rate ratio (IRR), 1.03; 95% confidence interval (95% CI), 1.02-1.05], greater time since transplantation (P < 0.001), smoking (IRR, 2.13; 95% CI, 1.12-4.07), and current use of azathioprine (IRR, 2.67; 95% CI, 1.39-5.15) or cyclosporine (IRR, 1.63; 95% CI, 1.00-2.65). Female sex (IRR, 0.29; 95% CI, 0.18-0.46) and non-Australian/New Zealand country of birth (P = 0.006), surrogate indices of reduced exposure to solar UV radiation, were significantly protective. Lip cancer after transplantation is strongly related to the current receipt of immunosuppression. During transplant function, lip cancer risk is associated with the duration of immunosuppression, receipt of specific immunosuppressive agents, and UV exposure.

Managing cancer risk and decision making after kidney transplantation

Kidney transplant recipients are at higher risk of cancer at most sites, and cancer after transplantation causes considerable morbidity and mortality. To optimize long-term patient outcomes, clinicians balance the prospect of graft failure and dialysis, with competing risks of diabetes, cardiovascular and cerebrovascular disease and the risk of malignancy. In this paper we critically examine the assumptions underpinning primary prevention, immunization, chemoprevention and screening programs, and highlight considerations when applying evidence to the kidney transplant population, and suggest a clinical research agenda that aims to define a rational approach to managing posttransplant cancer risk.

Cancers after renal transplantation

For patients with end-stage kidney failure, kidney transplantation improves both their quality of life and overall life expectancy compared with dialysis, but it is not without adverse effects. Cancer is second to cardiovascular disease as one of the major causes of morbidity and mortality in renal transplant recipients. Prolonged use of modern immunosuppression, which leads to alteration of immune function and immune surveillance, is associated with increased cancer risk. There is now convincing evidence from observational studies and registry data to confirm a 3- to 5-fold increase in overall cancer incidence, with viral-related neoplasia incurring the greatest risk when compare with the general population. Despite the increased risk, little is known about the overall cancer prognosis, screening, treatment strategies, and effectiveness in this population. Cancers can recur, occur de novo, and be transmitted from donor organs posttransplantation. Uncertainties exist as to how modern immunosuppressive agents impact on cancer management and outcomes in these patients, with some agents such as calcineurin inhibitors and azathioprine, being more carcinogenic than others. The newer agents, proliferation signal/mammalian target of rapamycin inhibitors and mycophenolate mofitil, may have some antiproliferative and antitumor activities demonstrated in preclinical and clinical studies, but long-term well-powered trial data are needed to determine whether they are either protective or curative for cancers in renal transplant recipients. In this review, the incidence, etiology, prognosis, and potential approaches to cancer screening and management post-renal transplantation are discussed.

Epithelial-to-mesenchymal transition in early transplant tubulointerstitial damage

It is unknown whether epithelial-to-mesenchymal transition (EMT) leads to tubulointerstitial fibrosis in renal transplants. In this study, interstitial fibrosis and markers of EMT were followed in protocol transplant biopsies in 24 patients. Tubulointerstitial damage (TID) increased from 34 to 54% between 1 and 3 mo after transplantation. Detection of EMT depended on the marker used; low levels of alpha-smooth muscle actin were found in 61% of biopsies, but the less specific marker S100 calcium binding protein-A4 (also known as Fsp1) suggested a higher incidence of EMT. The presence or development of TID did not correlate with EMT but instead significantly correlated with subclinical immune activity (P < 0.05). Among biopsies showing TID, microarray analysis revealed differential regulation of 127 genes at 1 mo and 67 genes at 3 mo compared with baseline; these genes were predominantly associated with fibrosis, tissue remodeling, and immune response. Of the 173 EMT-associated genes interrogated, however, only 8.1% showed an expression pattern consistent with EMT at 1 mo and 6.3% at 3 mo. The remainder were not differentially altered, or their changes in expression were opposite those expected to promote EMT. Quantitative reverse transcriptase-PCR revealed that the expression pattern of 12 EMT-associated genes was inconsistent over time, opposite that expected, or consistent with subclinical rejection or inflammation. In conclusion, EMT does not seem to play a significant role in the development of early allograft fibrosis.

How can we achieve global equity in provision of renal replacement therapy?

There is a significant emerging burden of chronic and end-stage kidney disease in low- and middle-income countries, driven by population ageing and the global epidemic of type 2 diabetes. Sufferers of end-stage kidney disease require ongoing dialysis or kidney transplantation to survive; however, in many low- and middle-income countries, treatment options are strictly limited or unaffordable. Low numbers of maintenance dialysis patients and transplant recipients reflect profound economic and service provision challenges for health-care systems in low- and middle-income countries in sustaining renal replacement therapy programmes. Underdeveloped organ donor and transplant programmes, health system and financing issues, ethical regulation of transplantation and the cost of pharmaceuticals commonly pose additional barriers to the delivery of efficient and cost-effective renal replacement therapy. Development of locally appropriate transplant programmes, effective use of nongovernmental sources of funding, service planning and cost containment, use of generic drugs and local manufacture of dialysis consumables have the potential to make life-saving renal replacement therapy available to many more in need. Select low- and middle-income countries demonstrate more equitable provision of renal replacement therapy is possible outside high-income countries. For other low- and middle-income countries, education, the development of good public policy and a supportive international environment are critical. Prevention of end-stage kidney disease, ideally as part of an integrated approach to chronic vascular diseases, must also be a key objective.

Cancer screening in renal transplant recipients: what is the evidence?

Increased cancer risk is well established in the renal transplant population. Little, however, is known about the benefits and harms of cancer screening, treatment effectiveness, and the overall cancer prognosis in renal transplant recipients. In this study, we critically appraised guidelines for cancer screening in the renal transplant and general populations using standard criteria for an evidence-based screening program. Guidelines were included when they were applied to adult participants, had objectives specific to cancer screening, and were written in English. Recommendations for breast and colorectal cancer screening in the general population were supported by evidence of cancer-specific mortality benefits from randomized, controlled trials of cancer screening. Convincing evidence from observational studies had demonstrated population cervical cancer screening was effective, also, test performance of mammography, faecal occult blood testing, and Pap smear were accurate. Population breast, colorectal, and cervical cancer screening also appeared to be good value for money in the general population. On the contrary, recommendations for cancer screening in renal transplant recipients were entirely extrapolated from data in the general population. Studies in the general population have led to the development of cancer screening guidelines in transplant recipients. Because of increased cancer risk, differences in diagnostic test performance, competing risks for deaths from causes such as cardiovascular disease and reduced overall life expectancies, validity of their recommendations are uncertain. Future studies are needed to address these issues to provide the necessary evidence for informed decision-making.

Transplant glomerulopathy: ultrastructural abnormalities occur early in longitudinal analysis of protocol biopsies

Transplant glomerulopathy (TXG) presents a distinctive pattern of glomerular abnormalities. The aim of this study was to describe its sequential ultrastructural pathology. A paired cohort study of 228 protocol biopsies, from our longitudinal database (n = 1345), compared TXG (7 patients, 95 biopsies) and controls (8 patients, 133 biopsies). Ultrastructural morphometry and C4d immunoperoxidase were evaluated from implantation to 5 years after transplantation against sequential histology and functional changes. TXG was predated by early glomerular endothelial cell activation; typified by vacuolation, hypertrophy, serration and expansion of lamina rara interna from 39 +/- 23 days after transplantation. Endothelial cells were transformed into an activated phenotype, containing numerous mitochondria, Golgi and ribosomes. Transition from fenestrated to continuous endothelium, mesangial matrix expansion and podocyte fusion occurred late. Endothelial cell activation also occurred in peritubular capillaries (PTC) followed by basement membrane multi-lamination (p < 0.05-0.001). Light microscopy changes of TXG occurred at 2.3 years. PTC C4d deposition was intermittently expressed over time, correlating with endothelial abnormalities, glomerular C4d and donor-specific antibodies (DSA) (p < 0.05-0.001). In summary, endothelial and subendothelial ultrastructural abnormalities in glomerular and peritubular capillaries are sensitive, early markers of TXG, likely due to stimulation of endothelial cells into an activated phenotype by antibody-mediated sub-lytic complement deposition.

Identifying high risk groups and quantifying absolute risk of cancer after kidney transplantation: a cohort study of 15,183 recipients

Transplant recipients have increased cancer risk, but data on risk variation across different patient groups are sparse. Rates and standardized rate ratios (SRR) of cancer (all sites, excluding nonmelanocytic skin and lip cancer) compared to the general population were calculated, using Australia and New Zealand Dialysis and Transplant Registry data. Within the transplant population, risk factors were identified (hazard ratios: HR; 95% CI) and absolute risk estimated for recipient groups. A total of 1642 (10.8%) of 15 183 recipients developed cancer. Risk was inversely related to age (SRR 15-30 children, 2 if >65 years). Females aged 25-29 had rates equivalent to women aged 55-59 from the general population. Age trend for lymphoma, colorectal and breast risk was similar; melanoma showed less variability across ages, prostate showed no risk increase. Within the transplanted population, risk was affected by age differently for each sex (p = 0.007), elevated by prior malignancy (HR 1.40; 1.03-1.89), white race (HR 1.36; 1.12-1.89), but reduced by diabetic end-stage kidney disease (ESKD) (HR 0.67; 0.50-0.89). Cancer rates in kidney recipients are similar to nontransplanted people 20-30 years older, but absolute risk differs across patient groups. Men aged 45-54 surviving 10 years have cancer risks varying from 1 in 13 (non-white, no prior cancer, diabetic ESKD) to 1 in 5 (white, prior cancer, other ESKD).